Crustal extension in the Tongariro graben, New Zealand: Insights into volcano-tectonic interactions and active deformation in a young continental rift

Research at the Tongariro graben, New Zealand, reveals that tectonic faulting dominates crustal extension over magma intrusion in this young continental rift. The study quantifies geological extension at 7 ± 1.2 mm/yr since 20 ka, with 78%–95% (5.8–7.0 mm/yr) attributed to tectonic activity and only 5%–22% (0.4–1.6 mm/yr) linked to dike intrusions, including volcanic eruptions and deep arrested dikes. Field observations and theoretical fault dislocation modeling were used to distinguish between tectonic and volcano-tectonic faults. These findings refine seismic and volcanic hazard assessments for the region and provide insights into volcano-tectonic interactions in similar continental rifts worldwide.

Gómez-Vasconcelos, M. G., Villamor, P., Cronin, S., Procter, J., Palmer, A., Townsend, D., & Leonard, G. (2017). Crustal extension in the Tongariro graben, New Zealand: Insights into volcano-tectonic interactions and active deformation in a young continental rift. GSA Bulletin, 129(9-10), 1085–1099. https://doi.org/10.1130/b31657.1